If one word sums up the life and work of Anna Politkovskaya, Russia's foremost investigative reporter assassinated at the age of 48, it is bravery. She could have chosen another life. Born and raised in New York, the daughter of Ukrainian UN diplomats, she was part of a Soviet elite that looked after its own. As a child, she had the best of both worlds: her parents could smuggle banned books out of the country, so she could write her dissertation about whomever she pleased. She alighted upon a poet shunned by Moscow, the émigré Marina Tsvetayeva.

She took from her background the social self-confidence that comes from rubbing shoulders with four-star generals round the kitchen table. But the earth was moving under the Soviet empire, and unlike many of her circle who saw perestroika as an opportunity to cash in their privilege, Politkovskaya moved instinctively in the opposite direction. After graduating in journalism from Moscow State University in 1980, she joined the daily Izvestia, before switching to the small independent press, first with Obshchaya Gazeta, then Novaya Gazeta.

She never saw herself as a war correspondent; indeed, Russia's first disastrous foray into Chechnya, from 1994 to 1998, almost passed her by. It is an irony of her story that the war she did not write about was brought to a halt by crusading journalism. Nightly reports chronicling the civilian cost of Russian artillery bombardments, broadcast on the independent television station NTV, had the same effect as the coverage of Vietnam had done on American audiences 30 years earlier. The Kremlin opted to sue for peace.

At the time, Politkovskaya was writing about state orphanages and the plight of the old: "I was interested in reviving Russia's pre-revolutionary tradition of writing about our social problems. That led me to writing about the seven million refugees in our country. When the war started, it was that that led me down to Chechnya."

By the start of the second Chechen war in 1999, the Kremlin had learned its lessons. The absence of reporting from the other side and lock-down on the battlefield put the Federal Security Service (FSB) in charge and set Chechen against Chechen. That was when Politkovskaya came into her own as a campaigning journalist.

She was in little doubt that Russia had been provoked. The relatively moderate wing of Chechen resistance, led by its former president Aslan Maskhadov, had run out of money. Into the vacuum swept money from the Wahabbis and foreign fighters like the Arab known as Khattab. When 9/11 provided an international parallel, it was only too convenient for the Russian president, Vladimir Putin. Shamil Basayev (obituary, July 11), a Chechen warlord who dreamed of creating a Muslim state across the north Caucasus, linked up with Khattab and invaded Dagestan, a fragile patchwork of Christian and Muslim tribes and part of the Russian Federation.

Politkovskaya agreed that Russia had to react. "But it was the way they did it," she said. "It was clear to me it was going to be total war, whose victims were first and foremost going to be civilian."

What followed was an excoriating series of articles and two books baring Russia's soul to the atrocities committed in its name - events like the "cleansing operation" of a village called Starye Atagi from January 28 to February 5 2002, and the shooting of six innocent villagers on a bus by members of a GRU military intelligence patrol, who then set fire to the vehicle to make it look as if it had been hit by rebel rockets. Politikovskaya always said she wrote for the future; indeed, court action about that incident grinds on to this day.

Her first book, A Dirty War: A Russian Reporter in Chechnya (2001), chronicled not so much what Russia was doing to Chechnya, but what Chechnya was doing to Russia. Putin's Russia (2004) described how new Russians got their money, through a combination of violence and old-fashioned thievery: it was to save the dying embers of democracy at home that she flew repeatedly back into the cauldron of the north Caucasus.

Politkovskaya had already used up several of her nine lives as a reporter. She had been locked in a hole in the ground by Russian troops and threatened with rape, kidnapped, and poisoned by the FSB on the first flight to Rostov after the Beslan school siege in 2004. She had acted as a negotiator in the Dubrovka theatre siege in Moscow in 2002, when 129 people died after the special services released gas into the building. In 2001, she had been forced to flee to Vienna. But she always came back for more, even at personal cost. Her husband left her. Her son pleaded with her to stop. Her neighbours, cowed by the attentions of the FSB in an upmarket street in central Moscow, shunned her.

For months she had been focusing on Ramsan Kadyrov, the son of a murdered Chechen president, who nurtured presidential ambitions himself. For some time, according to Politkovskaya, he had been telling anyone who would listen that her days were numbered. "The women in the crowd tried to conceal me because they were sure the Kadyrov people would shoot me on the spot if they knew I was there," Politkovskaya said. "They reminded me that Kadyrov publicly vowed to murder me. He actually said during a meeting of his government that Politkovskaya was a condemned woman."

In the last interview she gave, to the independent Radio Svoboda, Politkovskaya said she planned to publish in today's Novaya Gazeta the results of a large investigation into torture in Chechnya. The article was never sent. She is survived by her son Ilya and daughter Vera.